<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>

        .fade-enter-active, .fade-leave-active {
          transition: opacity .5s
        }
        .fade-enter, .fade-leave-active {
          opacity: 0
        }
    </style>
    <input type="button" value="按钮" @click="toggle">
    <transition name="fade">
        <div id="div1" v-show="isShow" transiton="fade"></div>
    </transition>
</head>
<body>
    <div id="box">
        <input type="button" value="按钮" @click="toggle">
        <transition name="fade">
            <div id="div1" v-show="isShow" transiton="fade">aaaaa</div>
        </transition>
    </div>
</body>
</html>